Drain

ABSTRACT

A grid drain for use on a sink to prevent large objects from entering the drain. The drain includes a tube ( 12 ) and a cover ( 20 ) that attaches to the top of the tube. The cover has a flat middle ( 72 ) and has a peripheral portion ( 74 ) that is curved to form a dome, with two circles of holes ( 46, 52 ).

BACKGROUND OF THE INVENTION

Sinks that temporarily hold fluid such as water, commonly have a drain through which water rapidly leaves. The drain has holes that pass small solid objects such as hair without the hair blocking the drain. It is desirable to construct the drain so the holes are oriented and shaped to minimize blockage from debris.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the invention, a grid drain is provided that can be constructed at low cost and that minimizes blocking. By increasing air flow through the drain, the drain can be used as a cleanout to service the drain. The drain includes a vertical tube and a dome cover that is removably mounted on the top of the tube, the cover having multiple holes. The cover holes are arranged in two circles, including a middle circle where the cover is flat (horizontal), and an outer circle where the cover is curved to form a dome.

The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a drain of the invention, with the cover attached to the tube.

FIG. 2 is an exploded enlarged view of a top portion of the drain tube and of the cover.

FIG. 3 is a sectional view taken on line 3 of FIG. 5.

FIG. 4 is an isometric view of the cover of FIG. 3.

FIG. 5 is a plan view of the cover of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a drain 10 of the invention, which includes a tube 12 that extends along a vertical axis 14 and a cover 20 that is mounted on the top of the tube. FIG. 2 shows that the tube 12 has a flange 22 at its top, that forms a support surface 24. The cover has a periphery 30 with three downward projections 31 that lie on the support surface. A vandal resistant screw 32 (FIG. 4) passes through a hole 34 in the cover and screws into a threaded hole 36 at the top of the tube, to hold the cover in place. The screw has a pair of holes that allow it to be screwed only by a special tool. The cover is preferably a cast metal part.

The cover 20 (FIG. 2) is symmetrical about the vertical axis 14. The cover has two rings of holes, including an inner ring 40 and an outer ring 42. As shown in FIG. 5, the outer ring 42 has sixteen outer holes 44 that are uniformly (by 22.5°) spaced about a circle 46 centered on the axis. The inner ring 40 has eight inner holes 50 that are uniformly (by 45°) spaced about a circle 52. As shown in FIG. 5, each inner hole lies on an imaginary radial (to axis 14) line 54 and each outer hole lies on an imaginary radial line 60, with lines 60 angled apart by 22.5° and lines 54 angled apart by 45° and lying halfway between pair of lines 60.

FIG. 3 shows that the cover has a top part, or top plate part 70 with a flat (horizontal) middle portion 72 and with a curved outer part, or periphery 74. The periphery 74 extends in a quarter circle as seen in the sectional view of FIG. 3, with the upper surface 80 and the lower surface 82 parallel and each curved by one-quarter circle. This results in the cover forming a dome, with only the periphery of the cover being curved. In a cover that applicant has constructed, the over had a diameter of 2.6 inch, and a cover thickness of 0.1 inch. The bottom and top surfaces of the periphery were each curved about a point 84 lying 0.7 inch below the top plate part 70. The point 84 is spaced from the axis 14 by an amount A that is more than half the radius of the cover and by the height B of the cover. The cover is formed with the three bottom projections 31 that each lies against a support surface. The above construction results in a cover with uniformly stiff wall holes and with the holes occupying a maximum amount of the area of the cover.

The inner ring 40 of holes have hole axes 92 that are vertical. This allows efficient flow because when water reaches the inner holes 40, the water is moving close to the vertical. The outer ring 42 of holes have hole axes 94 (FIG. 4) that are angled about 45° from the vertical and from the horizontal (i.e. the outer hole axes 42 extend 15° to 75° to the vertical and to the horizontal), which is parallel to the direction of water flow through the cover. The top 100 (FIG. 2) of the outer holes face upward while the bottom 102 of the outer holes face horizontally. Solid particles, especially hair, tend to easily flow through the cover as they flow with the movement of water. Applicant can construct the drain in a number of ways, but prefers to make it of cast metal.

Thus, the invention provides a drain that facilitates the flow of water and of solid particles such as hair. The drain includes a cover of a generally dome shape, formed by a curved periphery and a flat (horizontal) middle. Holes in the cover include a ring of inner holes that lie in a flat (horizontal) wall of the cover, while a ring of outer holes lies in a curved periphery of the cover. The inner holes have vertical hole axes. The outer holes have axes that are angled about an eighth circle (about 45°) from the horizontal and from the vertical. The fact that the cover 20 is held by a screw and therefore can be easily removed from the tube 12, allows a plumber to remove the cover and run a “snake” through the tube and pipes to clean them.

Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents. 

What is claimed is:
 1. A drain that allows water to pass through while blocking large pieces of solid material, said drain including a tube (12) with a vertical axis (14) and a tube top forming a support surface (24), said drain including a cover (20) that covers said tube top and that has a plurality of drain holes, wherein: said cover is dome-shaped, with a cover periphery (30) that lies on said tube support surface, and with a cover top (70) lying along said vertical axis, said cover having a ring of inner holes (50) spaced about said axis and said cover has a ring of outer holes (44) spaced about said axis and lying further from said axis than said inner holes; each of said inner holes has a primarily vertical hole axis (92) and each of said outer holes has a center with an outer hole axis (94) angled between 15° and 75° to said tube vertical axis.
 2. The drain described in claim 1 wherein: said cover has twice as many of said outer holes as said inner holes, with each outer hole lying radially halfway between two inner holes as seen in a top view taken along said axis.
 3. The drain described in claim 1 wherein: said cover has a flat middle portion (72) lying on said axis, that forms said inner holes; said cover has a radially outer part (74) that is radially spaced from said vertical axis by more than half a radius of said cover periphery, with said outer part having curved inner and outer surfaces, that form a dome.
 4. A drain that allows water to pass through while blocking solid material, said drain including a tube with a vertical axis and an open top, and a cover that covers said open top and that has a plurality of holes, wherein: said cover is dome-shaped, with a cover periphery (30) that lies on said tube top, with a cover upper part (70) having an inner circle of holes (40), and with a cover peripheral portion (70) having an outer circle of holes (46); said holes of said outer circle of holes having vertical axis (92) and said holes of said lower circle of holes have axes angled between 15° and 75° from the vertical.
 5. The drain described in claim 4 wherein: said cover has a periphery with top and bottom surfaces (80, 82) that each extends in a quarter of a circle, as seen in a sectional view taken on said vertical axis, to form said dome. 